Vibratory compacter



Feb. 18, 1969 J. A. BRAFF ET AL VIBRATORY COMPACTER Sheet Filed Sept. 13. 1965 0 WW m m x i a; 1.4 1M

4 TTOPA/EYS Feb. 18, 1969 J. A. BRAFF ET AL I 3,427,939

VIBRATORY COMPACTER Filed Sept. 13, 1965 Sheet .2 of2 IN VENTORS JOSfPI/ 4. lava/:4-

United States Patent Office 3,427,939 Patented Feb. 18, 1969 Claims ABSTRACT OF THE DISCLOSURE A steerable vibration compacter for use on tractormounted booms (dip-sticks) to tamp back fill on level and inclined surfaces. Compaction unit is unsprung and comprises bottom plate carrying motor for rotated eccentric weights about a horizontal axis, frame for motor, housing, etc. Axis of rotation of eccentrics is in the horizontal plane of the center of gravity of compacter unit. Inwardly convergent stiff springs are connected to housing so that axes of springs substantially intersect the horizontal plane of center of gravity equidistantly about a vertical axis through center of gravity of compaction unit. The convergent springs are connected to a top plate by which constant pressure perpendicular to bottom plate is applied to compaction unit by the dip-stick, which also steers unit in directions perpendicular to direction of pressure. Convergence of springs on center of gravity plane overcomes tendency of compaction unit to walk out from under dip-stick, either under perpendicular pressure of dip-stick or opposite to a sidewise direction in which the unit is steered by the dip-stick.

This invention relates to a vibratory compacter which is particularly advantageous for compacting soil in confined areas, such as trenches, around building foundations, or on relatively steep embankments.

Prior to the present invention, the soil compacting machines used in closely confined areas and on relatively steep embankments have generally been hand-operated machines of relatively low power. Such machines are severely limited as to the depth of back fill which they can compact effectively in one pass, and consequently their use was relatively expensive in time and labor. Also, they are very difiicult to use on steep embankments at confined locations.

On the other hand, the conventional tractor-operated compacters used on large area sites, such as roads, were not well adapted for use in confined areas, such as trenches, or on relatively steep, confined embankments, such as near bridges or retaining walls.

The present invention overcomes this problem by providing a novel and improved compacter designed for tractor operation and particularly adapted for compacting soil in confined areas and on relatively steep embank ments at an efiective rate of speed much faster than can I be attained with conventional hand-operated compacters previously used for this purpose.

It is a principal object of this invention to provide such a compacter having improved maneuverability which enables it to be accurately controlled in response to the movement of a tractor-mounted boom.

Another object of this invention is to provide such a compacter of novel construction which substantially avoids any tendency for it to move in a jerky, non-uniform fashion over the ground.

Another object of this invention is to provide such a compacter of novel construction which is substantially free of excessive back-and-forth, pendulum-like movement when it is lifted up from the ground and swung to a new position by the tractor-mounted boom.

Another object of this invention is to provide such a compacter of novel construction which enables it to be positioned accurately at a desired angle by the tractormounted boom for compacting the soil on a sloping embankment.

Further objects and advantages of this invention will be apparent from the following detailed description of a presently-preferred embodiment thereof, which is illustrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a perspective view of the present vibratory compacter, shown in full lines on the end of a tractormounted boom, which is shown in phantom;

FIGURE 2 is a top plan view of the compacter of FIG. 1;

FIGURE 3 is a vertical longitudinal section through this compacter taken along the line 33 in FIG. 2 and with the vibration-absorbing springs omitted for simplicity;

FIGURE 4 is a fragmentary perspective view showing the rotary eccentric weight mounted in a support frame in the present compacter; and

FIGURE 5 is a fragmentary end view taken along the line 5-5 in FIG. 3 and showing one of the four vibrationabsorbing springs in the present compacter.

Referring first to FIGURE 1, the vibratory compacter of the present invention comprises a top frame pivotally connected at a first cross pin 11 to the free end of a socalled dip-stick 12 on a conventional tractor-mounted boom. Through this pivotal connection the dip stick can move the compacter horizontally and also can raise or lower it. A conventional pivotal linkage 13 on the dip stick couples a second cross pin 14 of this top frame to the piston rod 15 of a conventional hydraulic cylinderand-piston on the tractor-mounted boom. By suitable controls located on the tractor, the operator can selectively determine the angular position of the compacter with respect to the dip stick 12. Also, he can control the downward force which the dip stick 12 exerts on the compacter.

The top frame 10 comprises a rectangular horizontal bottom plate 16 and a pair of spaced, upstanding sides 17 and 18 which support the cross pins 11 and 14. The top frame also has four downwardly and outwardly inclined legs 19, 20, 21 and 22 which are rigidly attached to the underside of the bottom plate 16 near its respective four corners. In the particular embodiment shown, each of these legs 19-22 extends outward and downward laterally as well as in a front-to-back direction. The two legs at each side of the top frame are inclined oppositely from the two legs at the opposite side. As best seen in FIG. 3, a bottom foot plate 23 is rigidly attached to the lower end of depending leg 19. This foot plate 23 carries a depending cylindrical part 24 whose axis is directed downward and inward opposite to the angular inclination of the respective leg 19. A similar foot plate construction is provided on each of the other depending legs 20-22 of the top frame 10.

Four coil springs 25, 26, 27 and 28 (FIGS. 1 and 2) are attached at their upper ends respectively to the respective foot plates on the depending legs 19-22 of the top frame 10. Referring to FIGS. 1 and 5, the foot plate 23 on leg 19 has an opening 29 and the upper end of spring 28 terminates in a laterally offset eye portion 30 which registers with this opening. A bolt 31 passes down through opening 29 and this eye portion 30 of the spring, and a nut and washer assembly 32, 33 on the bolt clamp this eye portion 30 of the spring tightly against the underside of foot plate 23. The upper end of coil spring 25 snugly encircles the depending cylindrical part 24 on foot 23 and is centered thereby.

Each of the other springs 2628 is connected to the foot plate on the respective leg 20, 21 or 22 in the same fashion.

These four springs 25-28 are attached at their lower ends to a vertically vibratory unit, which includes a generally cylindrical two-piece housing 34, and a base plate 36 rigidly attached to the lower end of this housing. The housing has a cylindrical bottom section 35 and a top cover 34 telescopically received in the bottom section 35 and welded to the latter. The bottom section 35 of the housing carries laterally projecting brackets 37. The bottom plate 38 of a support frame is engaged between the base plate 36 and the lower end of the bottom housing section 35 and the brackets 37 on the latter, as shown in FIG. 3. These parts are clamped together by respective bolt and nut assemblies 39, 40.

The support frame includes a pair of opposite, upstanding, channel-shaped sides 41 and 42, which are welded at their lower ends to the bottom plate 38 and extend upward from the latter inside the housing 34, 35. These sides at their upper ends rigidly support a top plate 43 to which a hydraulic motor 44 is rigidly bolted. The fluid supply and return lines 45 and 46 for this motor extend through an opening 47 in the top cover 34 of the housing. The opposite ends of these lines are suitably connected in the hydraulic system of the tractor. The hydraulic motor has a rotary output shaft 48 carrying a drive pulley 49 disposed inside the top cover 34 of the housing.

The upstanding sides 41, 42 of the support frame carry respective anti-friction bearings 50 and 51, which rotatably support a shaft 52. A pulley 53 fastened to shaft 52 (at'the right side of the support frame in FIG. 3) is coupled to the motor pulley 49 through a conventional V-belt 54. An eccentric weight 55 is secured to shaft 52 between the sides 41 and 42 of the support frame, as best seen in FIGS. 3 and 4.

With this arrangement, the eccentric weight 55 is rotated about the axis of the rotation of shaft 52 through the drive imparted to shaft 52 by the V-belt 54 driven by hydraulic motor 44. As the eccentric weight rotates its center of gravity moves successively above and below its axis of rotation so as to cause the entire vibratory unit, which includes the eccentric weight 55, the support frame 38, 41-43, hydraulic motor 44, pulleys 49 and 53, housing 34, 35 and base plate 36, to vibrate up and down and laterally.

The bottom section of housing 35 carries four similar laterally outwardly and downwardly inclined brackets 60, 61, 62 and 63, to which are attached the lower ends of the respective springs 25, 26, 27 and 28. As shown in FIG. 5, bracket carries an upwardly and outwardly inclined, upstanding, cylindrical part 64 which snugly receives and centers the lower end of spring 25. This part 64 is substantially aligned with the depending part 24 on the corresponding leg 19 of the top frame 10. The lower end of spring 25 terminates in an eye portion 65 which registers with an opening 66 in bracket 60. A bolt 67 and a nut and washer assembly 68, 69 fasten this eye portion 65 of spring 25 to bracket 60.

Each of the other springs 26, 27 and 28 is connected in the same fashion to the respective bracket 61, 62 or 63.

As explained hereinafter, in accordance With the preferred embodiment of this invention, the center of gravity of the entire vibratory unit (which includes base plate 36, support frame 38, 41-43, eccentric weight 55, motor 44, pulleys 49, 53 and housing 34, 35) is located substantially on the axis of rotation A (FIGS. 3 and 4) of the eccentric weight 55, and the lower ends of the springs 2528 are connected to this vibratory unit at substantially the horizontal plane On which this axis of rotation and center of gravity lie.

In operation, when there is substantial hydraulic pressure on the cylinder-and-piston unit associated with the top frame 10, the springs 25-28 will be under compression and will impart this downward hydraulic force to the vibratory unit, as well as absorbing the vertical and lateral vibrations of the vibratory unit to substantially avoid transmitting these vibrations to the top frame 10 and the dip stick 12. That is, while the vibratory unit vibrates, the dip stick 12 and the top frame 10 remain substantially fixed.

When the dip stick 12 is lifted, the springs 25-28 act as tension springs to impart this lift to the vibratory unit.

The canting of the springs 25-28 is an important feature of the preferred embodiment of the present invention which greatly enhances the maneuverability of the compacter. On all sides of the compacter (whether front and back or the ends), the springs at one side are inclined opposite to the springs at the opposite side. Each spring has a substantially greater stiffness axially than transverse to its axis. Because each spring axis is at an acute angle to the horizontal, and not perpendicular thereto, the axial spring resistance has a substantial component which is directed laterally of the compacter when the compacter is disposed substantially vertical for operation on horizontal ground. For any given direction of horizontal movement of the dip stick 12, the two springs at the trailing end of the vibratory unit, because of their angular inclination and axial stilfness, both provide a horizontal component of spring force which opposes the tendency of the horizontal force applied by the dip stick to displace the upper end of the spring horizontally with respect to its lower end. Consequently, as regards horizontal movement of the compacter, these springs serve as relatively tight couplings between the dip stick and the vibratory unit, so that the vibratory unit will move over the ground accurately in accordance with the horizontal movement of the dip stick and substantially free of any jerky movements such as would be likely if the springs could be easily flexed horizontally. That is, the springs have sufiicient stiffness laterally of the compacter that they effectively prevent substantial horizontal displacement of their upper ends with respect to their lower ends.

The lateral stiffness provided by the opposite canting of the springs also is advantageous when the compacter is lifted up and swung over to a new position by the tractor-operated dip stick. When this happens, the springs substantially overcome any tendency for the compacter to swing back and forth like a pendulum when the dip stick comes to a stop.

Also, the lateral stiffness provided by the canting of the springs improves the accuracy with which the vibratory unit can be positioned at an angle for use on an inclined embankment. When the linkage 13 is positioned to tilt the compacter so that its base plate 36 will be at an acute angle to the horizontal, the two springs which are the lower end of the now-tilted compacter will have their axes closer to the horizontal. Therefore, the axial stiffness of these springs will provide an increased horizontal component of spring force resisting the displacement of the vibratory unit horizontally with respect to the top frame 10. Consequently, the angular position of the top frame, as determined accurately by the boom linkage 13 in FIG. 1, will determine the angular position of the soil-engaging base plate 36 with much greater precision than was possible heretofore.

In accordance with another aspect of the present invention, the maneuverability of the compacter is further enhanced because the lower ends of the springs are connected to the housing 34, 35 in substantially the same horizontal plane as the axis of rotation A (FIGS. 3 and 4) of the eccentric 55, and the center of gravity of the entire vibrating unit (including housing 34, 35, base plate 36, motor 44, support frame 38, 41-43, eccentric weight 55 and pulleys 49, 53) is located substantially on this axis of rotation. By virtue of this novel construction, the relatively, heavy mass ofthe spring-suspended vibratory unit can be accurately positioned by the tractor-operated boom, and problems due to substantial weight unbalance of the vibratory unit where it is connected to the springs are substantially avoided.

Where the present compacter is to be used in relatively narrow ditches or other closely confined spaces, the angular inclination of the springs 25-28 may be modified so that the springs have no angular inclination laterally, but merely have an outward and upward inclination longitudinally (i.e., lengthwise of the ditch) because the horizontal movement of the compacter will be only in that direction, and not laterally.

While a presently-preferred embodiment of this invention has been described in detail and illustrated in the accompanying drawings, it is to be understood that the invention is susceptible of other structural embodiments which differ from the particular embodiment disclosed.

We claim:

1. A vibratory compacter comprising:

a top frame for connection to means for imposing a vertical force on the top frame and for moving the top frame horizontally;

a vibratory unit spaced below said top frame and including a base plate and a motor-driven vibrating mechanism disposed above said base plate and coupled to the latter for vibration in unison therewith; and

a plurality of springs having their lower ends connected to said vibratory unit at spaced locations around the latter, the springs on opposite sides of said vibratory unit being oppositely inclined upwardly and outwardly from their respective lower ends and having their upper ends connected to said top frame from imparting to said vibratory unit a downward force imposed on the top frame and for substantially absorbing the vibrations of said vibratory unit.

2. A vibratory compacter comprising:

a top frame for connection to means for imposing a vertical force on the top frame and for moving the top frame horizontally;

a vibratory unit spaced below said top frame and including a base plate and a motor-driven vibrating mechanism disposed above said base plate and coupled to the latter for vibration is unison therewith, said vibratory unit having its center of gravity in a predetermbined horizontal plane of the unit; and

a plurality of springs having their lower ends connected to said vibratory unit at spaced locations around the latter substantially in said horizontal plane of the latter, the springs on opposite sides of said vibratory unit being oppositely inclined upwardly and outwardly from their respective lower ends and having their upper ends connected to said top frame for imparting to said vibratory unit a downward force imposed on the top frame and for substantially absorbing the vibrations of said vibratory unit.

3. A vibratory compacter comprising:

a top frame having means for pivotal connection to the end of a tractor-mounted boom and means for pivotal connection to a hydraulic cylinder-and-piston on the boom;

a vibratory unit spaced below said top frame, said vibratory unit including a base plate, a housing extending up from said base plate, a support frame extending up from said base plate within said housing, an eccentric weight rotatably supported within said housing by said frame, a drive motor within the housing, and drive means coupling said motor to said eccentric weight for imparting rotation to the latter to vibrate said housing, base plate, frame, motor and drive means in unison, said vibratory unit having its center of gravity located substantially on the axis of rotation of the eccentric weight; and

a plurality of springs disposed outside said housing hav- A vibratory compacter comprising:

top frame having means for pivotal. connection to the end of a tractor-mounted boom and means for pivotal connection to a hydraulic cylinder-and-piston on the boom;

vibratory unit spaced below said top frame, said vibratory unit including a base plate, a housing extending up from said base plate, a support frame extending up from said base plate within said housing, an eccentric weight rotatably supported within said housing by said frame above said base plate, a drive motor on said frame within the housing and spaced above said eccentric weight, and drive means coupling said motor to said eccentric weight for imparting rotation to the latter to vibrate said housing, base plate, frame, motor and drive means in unison, said vibratory unit having its center of gravity located substantially on the axis of rotation of the eccentric weight; and

plurality of springs disposed outside said housing having their lower ends connected to said vibratory unit at spaced locations around the periphery of the housing substantially in a horizontal plane of the latter where said axis of rotation is located, the springs on opposite sides of the housing being oppositely inclined upwardly and outwardly away from said housing and having their respective upper ends connected to said top frame for imparting to said vibratory unit a downward force imposed on said top frame by the boom and for substantially absorbing the vibrations of said vibratory unit.

A vibratory compacter comprising:

top frame having a first cross pin for pivotal connection to the end of a tractor-mounted boom and a second cross pin for pivotal connection to a hydraulic cylinder-and-piston on the boom, said top frame having a plurality of downwardly and outwardly extending legs, each terminating at its lower end in a foot member having a downwardly and inwardly inclined part;

vibratory unit spaced below said top frame, said vibratory unit including a base plate, a housing eX- tending up from said base plate, said housing having a plurality of brackets at spaced locations around its periphery, each of said brackets having an upwardly and outwardly inclined part in substantial alignment with the downwardly and inwardly inclined part on a respective foot member of the top frame, a support frame extending up from said base plate within said housing, an eccentric weight rotatably supported within said housing by said frame above said base plate, a drive motor on said frame within the housing and spaced above said eccentric weight, and drive means coupling said motor to said eccentric weight for imparting rotation to the latter to vibrate said a downward force imposed on said top frame by the housing, base plate, frame, motor and drive means boom and for substantially absorbing the vibrations in unison, said vibratory unit having its center of of said vibratory unit. gravity located substantially on the axis of rotation of the eccentric weight; and 5 References Cited a plurality of springsddisposeld outsiders-aid hgusing UNITED STATES PATENTS mg err ower en s snu y enclrc lng sal rupwar and outwardly inclined parts on said brackets and 5 5 "5 connected to said :brackets substantially in a horizon- 30O1458 9/1961 C n tal plane of said vibratory unit where said axis of rota- 10 3181442 5/1965 f i er 9 8 tion is located, the springs on opposite sides of the nge i 1 housing being oppositely inclined upwardly and outwardly away from said housing and having their FOREIGN PATENTS respective upper ends snugly encircling said down- 1,106,435 7/1955 Francewardly and inwardly inclined parts on the respective 15 930,677 9/ 1955 yfoot members of the top frame and connected to said foot members for imparting to said vibratory unit JACOB NACKENOFFPrma'y Exammer- 

